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World-Universe Model Predictions 认领
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作者 Vladimir S. Netchitailo 《高能物理(英文)》 2020年第2期282-297,共16页
In 2013, World-Universe Model (WUM) proposed a principally different way to solve the problem of Newtonian Constant of Gravitation measurement precision. WUM revealed a self-consistent set of time-varying values of Pr... In 2013, World-Universe Model (WUM) proposed a principally different way to solve the problem of Newtonian Constant of Gravitation measurement precision. WUM revealed a self-consistent set of time-varying values of Primary Cosmological parameters of the World: Gravitation parameter, Hubble’s parameter, Age of the World, Temperature of the Microwave Background Radiation, and the concentration of Intergalactic plasma. Based on the inter-connectivity of these parameters, WUM solved the Missing Baryon problem and predicted the values of the following Cosmological parameters: gravitation G, concentration of Intergalactic plasma, relative energy density of protons in the Medium, and the minimum energy of photons, which were experimentally confirmed in 2015-2018. Between 2013 and 2018, the relative standard uncertainty of G measurements decreased x6. The set of values obtained by WUM was recommended for consideration in CODATA Recommended Values of the Fundamental Physical Constants 2014. 展开更多
关键词 World-Universe Model DIMENSIONLESS Time-Varying PARAMETER Q Gravitational PARAMETER Hubble’s PARAMETER Age of the World TEMPERATURE of Microwave BACKGROUND RADIATION TEMPERATURE of FAR-INFRARED BACKGROUND RADIATION Peak Medium of the World Inter-Connectivity of Primary Cosmological Parameters Multicomponent Dark Matter Weak Interaction Intergalactic Plasma Neutrinos CODATA
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文章速递Mathematical Modeling of Landfill Gas (MSW)—Production of Gas with Methane Gas Content from Landfills (MSW) 认领
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作者 Danila Vieru 《地球科学和环境保护期刊(英文)》 2020年第12期36-62,共27页
The municipal solid waste (msw) is a source of landfill gas (msw)—with methane gas content. Preoccupations for landfill gas (msw) management date back since 1976 when, at a landfill (msw) in California (USA), it turn... The municipal solid waste (msw) is a source of landfill gas (msw)—with methane gas content. Preoccupations for landfill gas (msw) management date back since 1976 when, at a landfill (msw) in California (USA), it turned out practically that the landfill gas (msw) with methane gas content contains a gas with high caloric value that can be collected and used for economic purposes. The landfill gas (msw) contains methane gas (30% - 60% volume), carbon dioxide (45% - 50% volume), hydrogen sulfide and other gases. Methane gas, carbon dioxide, nitrous oxide and other gases are listed in Kyoto Protocol as high greenhouse gases. Their ecological-rational management is both a national and global preoccupation. In terms of greenhouse gases, especially methane gas, the landfill (msw) is held responsible for 3.5% - 5% of the total global greenhouse gases. Practically, the quantitative estimation of the methane gas in a municipal solid waste landfill can be done by measuring the landfill gas (msw) flow in an extraction-collection well. In Romania, a quantitative estimation relationship of methane gas from deposits (msw) was made, approaching the problem in a different way. This paper presents the calculation formula, the working algorithm, the municipal waste landfill equation and the NOMOGRAMA of a municipal solid waste landfill (msw). The NOMOGRAMA allows us to define the values for parameter -m- (number of months needed for an amount of municipal solid waste (msw) to degrade, starting with the year from which the landfill gas (msw) emission with methane gas content is calculated). Taking into account the environmental conditions for each location of municipal solid waste landfill, the calculation uses various indexes and approximations, while the fundamental parameter remains -m- defined by the NOMOGRAMA of the municipal solid waste landfill (msw). A municipal solid waste landfill (msw) is a conglomerate of waste with various biodegradation periods between 2 - 3 years and 5 - 10 - 30 years. Degradation of waste (msw) in to dissolved organic carbon will take place in a number of months defined -m- starting with the year from which the methane gas emission with the NOMOGRAMA of the municipal solid waste landfill (msw) is calculated. The -m- values for the year of the quantitative emission of methane gas can be also done analytically, which requires good experience in the ecologic-rational management of the municipal solid waste (msw). 展开更多
关键词 Municipal Solid Waste (MSW) NOMOGRAMA Calculation Formula Parameter -m- Quantitative Estimation of Methane Gas
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Numerical Calculations for a Boundary Layer Flow past a Moving Vertical Porous Plate with Suction/Injection and Thermal Radiation 认领
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作者 Okey Oseloka Onyejekwe Yohannes Demiss Belete Nahom Alemseged Worku 《应用数学(英文)》 2020年第3期172-183,共12页
The work presented herein investigates the velocity, heat transfer, Nusselt number and skin friction profiles involved in boundary layer flow past a moving vertical porous plate. Similarity transformations are employe... The work presented herein investigates the velocity, heat transfer, Nusselt number and skin friction profiles involved in boundary layer flow past a moving vertical porous plate. Similarity transformations are employed to convert the governing nonlinear unsteady momentum and energy equations from their partial differential equation forms to boundary value ordinary differential equations. The resulting equations are then solved numerically by the Runge-Kutta fourth order method with the help of a shooting technique. Several features of the flow and heat transfer characteristics for different values of problem parameters are analyzed and discussed. These include the effects of the radiation parameter (R), suction and injection parameter (c), Grashof (Gr) and Prandtl (Pr) numbers on the flow and heat profiles. Numerical results show the impact of blowing and sucking as well as radation on boundary layer flows of this type. Both the skin frictions as well as the heat transfer rate are also significantly related to the radiation parameter. For all these cases;the numerical results are found to be in agreement with the physics of the problem. 展开更多
关键词 MOMENTUM and Energy Grashof NUMBER Prandtl NUMBER Similarity Transformation RADIATION Parameter SUCTION BLOWING RADIATION Po-rous Plate
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Research on Energy Saving of Charging Based on Mathematical Modeling 认领
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作者 Ziyue Cai Weijie Li +1 位作者 Wenxuan Xu Zihan Zhao 《应用数学与应用物理(英文)》 2020年第3期555-583,共29页
This paper studies the change of electronic energy demand when people charge various kinds of electronic products (including small and large ones) in different places, as well as costs of meeting needs. By setting up ... This paper studies the change of electronic energy demand when people charge various kinds of electronic products (including small and large ones) in different places, as well as costs of meeting needs. By setting up a linear programming problem with the actual demand number of various charging carriers as decision variables, with the goal of the maximum cost reduction, and with the constraint of meeting needs of various customers, this paper finds out the lowest cost scheme. 展开更多
关键词 PARAMETER ESTIMATION COMPUTER Simulation LINEAR PROGRAMMING
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How Flat Space Cosmology Models Dark Energy 认领
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作者 Eugene Terry Tatum U. V. S. Seshavatharam 《现代物理(英文)》 2020年第10期1493-1501,共9页
Equations of Flat Space Cosmology (FSC) are utilized to characterize the model’s scalar temporal behavior of dark energy. A table relating cosmic age, cosmological redshift, and the temporal FSC Hubble parameter valu... Equations of Flat Space Cosmology (FSC) are utilized to characterize the model’s scalar temporal behavior of dark energy. A table relating cosmic age, cosmological redshift, and the temporal FSC Hubble parameter value is created. The resulting graph of the log of the Hubble parameter as a function of cosmological (or galactic) redshift has a particularly interesting sinuous shape. This graph greatly resembles what ΛCDM proponents have been expecting for a scalar temporal behavior of dark energy. And yet, the FSC <em>R</em><sub><em>h</em></sub><em> = ct </em>model expansion, by definition, neither decelerates nor accelerates. It may well be that apparent early cosmic deceleration and late cosmic acceleration both ultimately prove to be illusions produced by a constant-velocity, linearly-expanding, FSC universe. Furthermore, as discussed herein, the FSC model would appear to strongly support Freedman<em> et al.</em> in the current Hubble tension debate, if approximately 14 Gyrs can be assumed to be the current cosmic age. 展开更多
关键词 Flat Space Cosmology Dark Energy Hubble Parameter Galactic Redshift Rh = ct Model
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Counting the Microstates at the Black Hole Horizon and the Immirzi Parameter of Loop Quantum Gravity 认领
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作者 M. Sadiq 《应用数学与应用物理(英文)》 2020年第10期2055-2062,共8页
Motivated by Bekenstein’s original thought that led him to his famous area-entropy formula for a black hole and by our recent study regarding the black hole dynamics, we identify the appropriate microscopic degrees o... Motivated by Bekenstein’s original thought that led him to his famous area-entropy formula for a black hole and by our recent study regarding the black hole dynamics, we identify the appropriate microscopic degrees of freedom in loop quantum gravity that are responsible for the black hole entropy. We achieve consistent results by taking the <em>j</em> = 1/2 edges as dominant and by subjecting these edges to experience quantum fluctuations at the horizon. This also leads to a modification of the value of the Immirzi parameter in the <em>SU</em>(2) framework. 展开更多
关键词 Immirzi Parameter Spin Networks Quantum Gravity Loop Quantum Gravity Isotropic Oscillator SU(2) Quasinormal Modes Black Hole
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An Assessment on the Coastal Seawater Quality of the Gulf of Suez, Egypt 认领
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作者 Manal G. Mahmoud Ehsan Abu El-Khir +3 位作者 Mahmoud H. Ebeid Laila A. Mohamed Mamdouh A. Fahmy Kholoud S. Shaban 《环境保护(英文)》 2020年第1期34-47,共14页
The present study focused on water quality assessment of 14 hotspot locations in the Gulf of Suez by measuring the physicochemical parameters seasonally during 2016. The results of investigated area revealed that, the... The present study focused on water quality assessment of 14 hotspot locations in the Gulf of Suez by measuring the physicochemical parameters seasonally during 2016. The results of investigated area revealed that, the annual mean range of water was: temperature (21.91°C - 29.22°C), pH (7.64 - 7.78), salinity (38.71‰ - 42.74‰), dissolved oxygen (6.09 - 8.78 mgO2/l,) oxidizable organic matter (1.4 - 5.4 mg/l), biological oxygen demand (1.14 - 3.94 mgO2/l), total suspended solids (18.56 - 37.69 mg/l), ammonia (13.51 - 494.41 μg/l), nitrite (1.261 - 151.76 μg/l), nitrate (7.11 - 487.85), dissolved inorganic phosphate (2.22 - 53.26) and silicate (19.83 - 347.61 μg/l). The N:P ratio fluctuated between 4.21 and 1214.61 with the main value of 81.16 indicating that the different sites in the northern part of the Gulf of Suez are P-limited. Based on the Principal Component Analysis Data, the stations locating in the Northern and Southern side of the Gulf of Suez are relatively good water quality;meanwhile, water quality of the other stations locating in the northern side of the Gulf of Suez is found slightly polluted to a different degree co-incided with an increase in the human activities in each of these locations. 展开更多
关键词 The GULF of Suez Seawater Hydro-Chemical PARAMETER NUTRIENTS Water Quality INDEX (WQI)
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Space Observations and Global Climatic Data Reanalysis in AERMOD Modeling Package to Enhance the Industrial Air Pollution and Health Risk Assessment 认领
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作者 Marina Faminskaya 《地球科学和环境保护期刊(英文)》 2020年第7期65-83,共19页
We try to enhance the AERMOD industrial pollution dispersion model with remote sensing observations and climatic models based on them. In this paper, we focus on surface parameters (albedo, roughness, Bowen ratio) and... We try to enhance the AERMOD industrial pollution dispersion model with remote sensing observations and climatic models based on them. In this paper, we focus on surface parameters (albedo, roughness, Bowen ratio) and land use classification on which they depend. We model maximum hourly concentrations and the resulting acute health risk and assess the effect on them produced by using remote sensing data for local areas around industrial plants instead of global standard AERMOD parameters. We consider five real multi-source plants for the effect of classification and two of them for the effect of surface parameters. The effect on the critical pollutant is measured in three ways: a) as difference between the yearly maxima of hourly concentrations of a critical pollutant (“absolute”);b) the same limited to daytime workhours and 95% quantile instead of absolute maximum (“regulatory”);c) as maximum hourly difference over a year (“instant”). The measure of effect is divided either by the reference concentration of the pollutant, which yields the impact on health risk, or by the concentration obtained with AERMOD standards, which yields relative measure of impact. For a), the impact of roughness dominates, that of albedo is small and that of the Bowen ratio is almost zero. For b), the impact of roughness is less prominent, and that of albedo and Bowen ratio is noticeable. For c), the impact is considerable for all three parameters. The effect of land use classification is considerable in all three cases a) </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> c). We provide the figures for different measures of remote sensing data effect and discuss the perspective of using remote sensing data in regulatory context. 展开更多
关键词 Pollutant Dispersion Model AERMOD ALBEDO Bowen Parameter Roughness Landsat ALOS GLASS ERA5
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Effect of soil pore size distribution on plant-available water and least limiting water range as soil physical quality indicators 认领
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作者 Mehdi ZANGIABADI Manoochehr GORJI +2 位作者 Mehdi SHORAFA Saeed KHAVARI KHORASANI Saeed SAADAT 《土壤圈:英文版》 SCIE CAS CSCD 2020年第2期253-262,共10页
Soil pore size distribution(SPSD) is one of the most important soil physical properties. This research investigated the relationships of location and shape parameters of the SPSD curves with plant-available water(PAW)... Soil pore size distribution(SPSD) is one of the most important soil physical properties. This research investigated the relationships of location and shape parameters of the SPSD curves with plant-available water(PAW) and least limiting water range(LLWR) of the light-textured soils at the Torogh Agricultural Research Station in north-eastern Iran. Soil moisture release curve(SMRC), PAW and LLWR in matric heads of 100 and 330 h Pa for the field capacity and location and shape parameters of the SPSD curves of 30 soils with different texture and organic carbon contents were determined, and the variable relationships were statistically analyzed. The results showed that the median equivalent pore diameter(de), mean de, standard deviation(SD*), and skewness of the SPSD curves were significantly correlated with PAW(PAW330) and LLWR(LLWR330) measured in a matric head of 330 h Pa. Decrease in deand increase in the diversity of soil pore size(SD*) increased PAW330 and LLWR330. The SD* values of all the soil samples were lower than the optimal ranges suggested in literature. Neither PAW nor LLWR values were significantly different in the soils with the optimal modal deand those with non-optimal modal de. Optimal values of median and mean equivalent pore diameters and kurtosis of SPSD curves led to a significant improvement of PAW330 and LLWR330 as soil physical quality indicators. It was recommended to revise the optimal ranges for SD* and modal defor future studies. 展开更多
关键词 equivalent PORE diameter KURTOSIS location PARAMETER matric head shape PARAMETER SKEWNESS SOIL PORE size distribution curve SOIL water AVAILABILITY
Investigation of Quantum Entanglement through a Trapped Three Level Ion Accompanied with Beyond Lamb-Dicke Regime 认领
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作者 Rasim Dermez 《量子信息科学期刊(英文)》 2020年第2期23-35,共13页
In this study, our goal is to obtain the entanglement dynamics of trapped three-level ion interaction two laser beams in beyond Lamb-Dicke parameters. Three values of LDP, <span style="white-space:nowrap;"... In this study, our goal is to obtain the entanglement dynamics of trapped three-level ion interaction two laser beams in beyond Lamb-Dicke parameters. Three values of LDP, <span style="white-space:nowrap;"><em>η</em>=0.09, <span style="white-space:nowrap;"><em>η</em>=0.2 </span></span>and <span style="white-space:nowrap;"><em>η</em>=0.3 </span>are given. We used the concurrence and the negativity to measure the amount of quantum entanglement created in the system. The interacting trapped ion led to the formation of phonons as a result of the coupling. In two quantum systems (ion-phonons), analytical formulas describing both these measurements are constructed. These formulas and probability coefficients include first order terms of final state vector. We report that long survival time of entanglement can be provided with two quantum measures. Negativity and concurrence maximum values are obtained N = 0.553 and for LDP = 0.3. As a similar, the other two values of LDP are determined and taken into account throughout this paper. For a more detailed understanding of entanglement measurement results, “contour plot” was preferred in Mathematica 8. 展开更多
关键词 Entangled State Trapped Three-Level Ion Lamb-Dick Parameter Rabi Frequency Quantum Measures
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Parameter Sensitivity and Qualitative Analysis of Dynamics of Ovarian Tumor Growth Model with Treatment Strategy 认领
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作者 Md. Shah Alam Md. Kamrujjaman Md. Shafiqul Islam 《应用数学与应用物理(英文)》 2020年第6期941-955,共15页
In this paper, we are interested to find the most sensitive parameter, local and global stability of ovarian tumor growth model. For sensitivity analysis, we use Latin Hypercube Sampling (LHS) method to generate sampl... In this paper, we are interested to find the most sensitive parameter, local and global stability of ovarian tumor growth model. For sensitivity analysis, we use Latin Hypercube Sampling (LHS) method to generate sample points and Partial Rank Correlation Coefficient (PRCC) method, uses those sample points to find out which parameters are important for the model. Based on our findings, we suggest some treatment strategies. We investigate the sensitivity of the parameters for tumor volume, <em>y</em>, cell nutrient density, <em>Q</em> and maximum tumor size, <em>ymax</em>. We also use Scatter Plot method using LHS samples to show the consistency of the results obtained by using PRCC. Moreover, we discuss the qualitative analysis of ovarian tumor growth model investigating the local and global stability. 展开更多
关键词 Parameter Sensitivity Latin Hypercube Sampling Partial Rank Correlation Coefficient Scatter Plot MONOTONICITY Stability Analysis
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Melia’s R<sub>h</sub>= ct Model Is by No Means Flat 认领
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作者 Rainer Burghardt 《现代物理(英文)》 2020年第5期703-711,共9页
With the support of numerous arguments, it has been shown that Melia’s claim that his cosmological Rh = ct model is flat and infinite is erroneous. In contrast, the model is positively curved, closed and, therefore, ... With the support of numerous arguments, it has been shown that Melia’s claim that his cosmological Rh = ct model is flat and infinite is erroneous. In contrast, the model is positively curved, closed and, therefore, finite. With respect to results of Melia’s model, it is identical to our Subluminal Model. 展开更多
关键词 Globally and Locally FLAT COSMOS Melia’s Rh = CT MODEL SUBLUMINAL MODEL Curvature Parameter
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Modeling Transmission Dynamics of COVID-19 in Nepal 认领
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作者 Gauri Bhuju Ganga Ram Phaijoo Dil Bahadur Gurung 《应用数学与应用物理(英文)》 2020年第10期2167-2173,共7页
A novel coronavirus disease (COVID-19) is an infectious viral disease caused by SARS-CoV-2. The disease was first reported in Wuhan, China, in December 2019, and it has been epidemic in more than 110 countries. The fi... A novel coronavirus disease (COVID-19) is an infectious viral disease caused by SARS-CoV-2. The disease was first reported in Wuhan, China, in December 2019, and it has been epidemic in more than 110 countries. The first case of COVID-19 was found in Nepal on 23 January, 2020. Now the number of confirmed cases is increasing day by day. Thus, the disease has become a major public health concern in Nepal. The propose of this study is to describe the development of outbreak of the disease and to predict the outbreak in Nepal. In the present work, the transmission dynamics of the disease in Nepal is analyzed mathematically with the help of SIR compartmental model. Reported data from June 1<sup>st</sup> to June 17<sup>th</sup> 2020 of Nepal are used to identify the model parameters. The basic reproduction number of COVID-19 outbreak in Nepal is estimated. Predictions of the peak epidemic time and the final size of the epidemic are made using the model. Our work predicts that, after 125 days from June 1 the infection will reach the peak. In this work, a good correlation between the reported data and the estimation given by our model is observed. 展开更多
关键词 COVID-19 Compartmental Model Basic Reproduction Number Nepal Parameter Estimation
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Upward Transition Probabilities B(E2)↑ Properties Study of Even-Even <sup>104-114</sup>Ru Nuclei 认领
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作者 Tazul Islam Ruhol Amin +1 位作者 Md. Ashraful Alam Jobaidul Islam 《核科学与技术国际期刊(英文)》 2020年第3期129-137,共9页
In this research work, the upward transition probabilities for the transition levels, 0<sup>+</sup> → 2<sup>+</sup>, 2<sup>+</sup> → 4<sup>+</sup>, 4<sup>+</s... In this research work, the upward transition probabilities for the transition levels, 0<sup>+</sup> → 2<sup>+</sup>, 2<sup>+</sup> → 4<sup>+</sup>, 4<sup>+</sup> → 6<sup>+</sup> and 6<sup>+</sup> → 8<sup>+</sup> levels of even-even neutron rich <sup>104-114</sup>Ru isotopes have been calculated by using the Global Best Fit (GBF) method. In addition, the associated parameters such as, Quadrupole moment and Deformation parameter of even-even <sup>104-114</sup>Ru have been calculated. The dependency of these nuclear parameters shows the nuclear magic number tendency. 展开更多
关键词 Upward Transition Probability Quadrupole Moment Deformation Parameter Global Best Fit (GBF) Method
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A modified lumped parameter model of distribution transformer winding 认领
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作者 Qingqing Ding Yao Yao +5 位作者 Bingqian Wang Jingwei Fu Wei Zhang Chao Zeng Xiaoping Li Stanimir Valtchev 《全球能源互联网:英文版》 2020年第2期158-165,共8页
The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed paramete... The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed parameters model can depict the winding characteristics accurately,but it requires complex calculations.Lumped parameter model requires less calculations,but its applicable frequency range is not wide.This paper studies the amplitude-frequency characteristics of the lightning wave,compares the transformer modelling methods and finally proposes a modified lumped parameter model,based on the above comparison.The proposed model minimizes the errors provoked by the lumped parameter approximation,and the hyperbolic functions of the distributed parameter model.By this modification it becomes possible to accurately describe the winding characteristics and rapidly obtain the node voltage response.The proposed model can provide theoretical and experimental support to lightning protection of the distribution transformer. 展开更多
关键词 Wide band frequency response Distributed parameter model Lumped parameter model Distribution transformer Lightning protection
文章速递Secure Market Operation in Presence of Critical Model Parameters in State Estimation 认领
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作者 Yuzhang Lin Ali Abur Hanchen Xu 《现代电力系统与清洁能源学报(英文)》 SCIE EI CSCD 2020年第4期699-708,共10页
This paper is concerned about the impact of network parameter errors on the reliable operation and management of electricity markets.Specifically,the paper investigates the so-called critical parameters in a network m... This paper is concerned about the impact of network parameter errors on the reliable operation and management of electricity markets.Specifically,the paper investigates the so-called critical parameters in a network model whose errors cannot be detected or estimated due to the lack of local measurement redundancy.Due to this property of critical parameters,it will be impossible to detect,identify and correct errors in these parameters.Given the fact that electricity market applications are heavily model-dependent,the locational marginal prices(LMPs)can be shown to be seriously distorted in the presence of critical parameter errors.Furthermore,if such errors are maliciously injected by adversaries,they will go undetected.Meanwhile,prices and revenues associated with power transactions may be strategically manipulated.An approach for quantifying the impact of critical parameters on the management of electricity markets is proposed.Conditions related to network topology and measurement configuration leading to the appearance of critical parameters are classified,and meter placement strategies for avoiding critical parameters are presented as well.Simulation results obtained by using IEEE test systems are given to verify the proposed analysis and design methods. 展开更多
关键词 Anomaly detection cyber security electricity market parameter estimation power system modeling state estimation
文章速递曲线箱梁桥摩擦摆式减隔震支座参数分析 认领
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作者 陈刘明 《工程建设》 2020年第11期37-40,61,共5页
为研究摩擦摆式减隔震支座动力参数对曲线箱梁桥地震响应的影响,以某城市立交桥为例,考虑支座的不同曲面半径和摩擦系数⒉种参数的变化,利用Midas Civil软件建立空间有限元模型,对结构进行动态时程分析。结果表明:在地震力作用下,各墩... 为研究摩擦摆式减隔震支座动力参数对曲线箱梁桥地震响应的影响,以某城市立交桥为例,考虑支座的不同曲面半径和摩擦系数⒉种参数的变化,利用Midas Civil软件建立空间有限元模型,对结构进行动态时程分析。结果表明:在地震力作用下,各墩内力随参数变化差异显著,最大增幅为10%~36%;两联交接位置处的顺桥向相对位移波动明显,最大可达13%左右;支座参数能显著调整结构内力,因此针对此类桥型的抗震设计应重视参数选取的合理性。 展开更多
关键词 摩擦摆式减隔震支座 曲线箱梁桥 参数
文章速递Influence factors on natural frequencies of composite materials 认领
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作者 Bo WANG Feng ZHAO +1 位作者 Zixu ZHAO Kunpeng XU 《机械工程前沿:英文版》 SCIE CSCD 2020年第4期571-584,共14页
Compared with traditional materials, composite materials have lower specific gravity, larger specific strength, larger specific modulus, and better designability structure and structural performance. However, the vari... Compared with traditional materials, composite materials have lower specific gravity, larger specific strength, larger specific modulus, and better designability structure and structural performance. However, the variability of structural properties hinders the control and prediction of the performance of composite materials. In this work, the Rayleigh–Ritz and orthogonal polynomial methods were used to derive the dynamic equations of composite materials and obtain the natural frequency expressions on the basis of the constitutive model of laminated composite materials. The correctness of the analytical model was verified by modal hammering and frequency sweep tests. On the basis of the established theoretical model, the influencing factors, including layers, thickness, and fiber angles, on the natural frequencies of laminated composites were analyzed. Furthermore, the coupling effects of layers, fiber angle, and lay-up sequence on the natural frequencies of composites were studied. Research results indicated that the proposed method could accurately and effectively analyze the influence of single and multiple factors on the natural frequencies of composite materials. Hence, this work provides a theoretical basis for preparing composite materials with different natural frequencies and meeting the requirements of different working conditions. 展开更多
关键词 composite material hammering and frequency sweep test structural parameter natural frequency
文章速递Predicting Code Smells and Analysis of Predictions: Using Machine Learning Techniques and Software Metrics 认领
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作者 Mohammad YMhawish Manjari Gupta 《计算机科学技术学报:英文版》 SCIE EI CSCD 2020年第6期1428-1445,共18页
Code smell detection is essential to improve software quality, enhancing software maintainability, and decrease the risk of faults and failures in the software system. In this paper, we proposed a code smell predictio... Code smell detection is essential to improve software quality, enhancing software maintainability, and decrease the risk of faults and failures in the software system. In this paper, we proposed a code smell prediction approach based on machine learning techniques and software metrics. The local interpretable model-agnostic explanations (LIME) algorithm was further used to explain the machine learning model's predictions and interpretability. The datasets obtained from Fontana et al. were reformed and used to build binary-label and multi-label datasets. The results of 10-fold cross-validation show that the performance of tree-based algorithms (mainly Random Forest) is higher compared with kernel-based and network-based algorithms. The genetic algorithm based feature selection methods enhance the accuracy of these machine learning algorithms by selecting the most relevant features in each dataset. Moreover, the parameter optimization techniques based on the grid search algorithm significantly enhance the accuracy of all these algorithms. Finally, machine learning techniques have high potential in predicting the code smells, which contribute to detect these smells and enhance the software's quality. 展开更多
关键词 code smell code smell detection feature selection prediction explanation parameter optimization
文章速递轮毂电机内定子绕线机设计及其关键技术分析 认领
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作者 夏志平 江文清 +1 位作者 王晓伟 段慧云 《机械设计》 CSCD 北大核心 2020年第11期78-84,共7页
分析轮毂电机内定子的结构,制订了内定子的绕线工艺方案和绕线机的结构设计方案;根据线圈绕线运动规律,对比分析不同类型的加减速算法,选择速度-S型曲线用于排线伺服系统的控制,以避免排线轴换向过程中出现排线不均匀、堆积等突出问题,... 分析轮毂电机内定子的结构,制订了内定子的绕线工艺方案和绕线机的结构设计方案;根据线圈绕线运动规律,对比分析不同类型的加减速算法,选择速度-S型曲线用于排线伺服系统的控制,以避免排线轴换向过程中出现排线不均匀、堆积等突出问题,并制订了其加减速参数设置流程。最后根据绕线机控制要求,搭建基于"触摸屏+运动控制器"的控制系统,完成系统硬件的选型和设计及包括PLC梯形图、人机界面等系统软件的设计。试验证明,新研制的内定子绕线机具有自动化程度高、运行稳定等优点,能够满足生产需要和质量要求。 展开更多
关键词 绕线机 排线轴 参数 内定子
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